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From: Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>
To: Tamar Christina <Tamar.Christina@arm.com>,
	"gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Cc: nd <nd@arm.com>, Richard Earnshaw <Richard.Earnshaw@arm.com>,
	Marcus Shawcroft <Marcus.Shawcroft@arm.com>,
	Richard Sandiford <Richard.Sandiford@arm.com>
Subject: RE: [PATCH 2/7]AArch64 Add combine patterns for narrowing shift of half top bits (shuffle)
Date: Thu, 30 Sep 2021 08:54:13 +0000	[thread overview]
Message-ID: <PAXPR08MB692622033D5EF44685B9781693AA9@PAXPR08MB6926.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <20210929161942.GA28881@arm.com>



> -----Original Message-----
> From: Tamar Christina <Tamar.Christina@arm.com>
> Sent: Wednesday, September 29, 2021 5:20 PM
> To: gcc-patches@gcc.gnu.org
> Cc: nd <nd@arm.com>; Richard Earnshaw <Richard.Earnshaw@arm.com>;
> Marcus Shawcroft <Marcus.Shawcroft@arm.com>; Kyrylo Tkachov
> <Kyrylo.Tkachov@arm.com>; Richard Sandiford
> <Richard.Sandiford@arm.com>
> Subject: [PATCH 2/7]AArch64 Add combine patterns for narrowing shift of
> half top bits (shuffle)
> 
> Hi All,
> 
> When doing a (narrowing) right shift by half the width of the original type
> then
> we are essentially shuffling the top bits from the first number down.
> 
> If we have a hi/lo pair we can just use a single shuffle instead of needing two
> shifts.
> 
> i.e.
> 
> typedef short int16_t;
> typedef unsigned short uint16_t;
> 
> void foo (uint16_t * restrict a, int16_t * restrict d, int n)
> {
>     for( int i = 0; i < n; i++ )
>       d[i] = (a[i] * a[i]) >> 16;
> }
> 
> now generates:
> 
> .L4:
>         ldr     q0, [x0, x3]
>         umull   v1.4s, v0.4h, v0.4h
>         umull2  v0.4s, v0.8h, v0.8h
>         uzp2    v0.8h, v1.8h, v0.8h
>         str     q0, [x1, x3]
>         add     x3, x3, 16
>         cmp     x4, x3
>         bne     .L4
> 
> instead of
> 
> .L4:
>         ldr     q0, [x0, x3]
>         umull   v1.4s, v0.4h, v0.4h
>         umull2  v0.4s, v0.8h, v0.8h
>         sshr    v1.4s, v1.4s, 16
>         sshr    v0.4s, v0.4s, 16
>         xtn     v1.4h, v1.4s
>         xtn2    v1.8h, v0.4s
>         str     q1, [x1, x3]
>         add     x3, x3, 16
>         cmp     x4, x3
>         bne     .L4
> 
> Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.
> 
> Ok for master?
> 

Ok.
Thanks,
Kyrill

> Thanks,
> Tamar
> 
> gcc/ChangeLog:
> 
> 	* config/aarch64/aarch64-simd.md
> 	(*aarch64_<srn_op>topbits_shuffle<mode>,
> 	*aarch64_topbits_shuffle<mode>): New.
> 	* config/aarch64/predicates.md
> 	(aarch64_simd_shift_imm_vec_exact_top): New.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* gcc.target/aarch64/shrn-combine-2.c: New test.
> 	* gcc.target/aarch64/shrn-combine-3.c: New test.
> 
> --- inline copy of patch --
> diff --git a/gcc/config/aarch64/aarch64-simd.md
> b/gcc/config/aarch64/aarch64-simd.md
> index
> d7b6cae424622d259f97a3d5fa9093c0fb0bd5ce..300bf001b59ca7fa197c580b
> 10adb7f70f20d1e0 100644
> --- a/gcc/config/aarch64/aarch64-simd.md
> +++ b/gcc/config/aarch64/aarch64-simd.md
> @@ -1840,6 +1840,36 @@ (define_insn
> "*aarch64_<srn_op>shrn<mode>2_vect"
>    [(set_attr "type" "neon_shift_imm_narrow_q")]
>  )
> 
> +(define_insn "*aarch64_<srn_op>topbits_shuffle<mode>"
> +  [(set (match_operand:<VNARROWQ2> 0 "register_operand" "=w")
> +	(vec_concat:<VNARROWQ2>
> +          (truncate:<VNARROWQ>
> +            (SHIFTRT:VQN (match_operand:VQN 1 "register_operand" "w")
> +	      (match_operand:VQN 2
> "aarch64_simd_shift_imm_vec_exact_top")))
> +	  (truncate:<VNARROWQ>
> +	    (SHIFTRT:VQN (match_operand:VQN 3 "register_operand" "w")
> +	      (match_dup 2)))))]
> +  "TARGET_SIMD"
> +  "uzp2\\t%0.<V2ntype>, %1.<V2ntype>, %3.<V2ntype>"
> +  [(set_attr "type" "neon_permute<q>")]
> +)
> +
> +(define_insn "*aarch64_topbits_shuffle<mode>"
> +  [(set (match_operand:<VNARROWQ2> 0 "register_operand" "=w")
> +	(vec_concat:<VNARROWQ2>
> +          (unspec:<VNARROWQ> [
> +              (match_operand:VQN 1 "register_operand" "w")
> +	      (match_operand:VQN 2
> "aarch64_simd_shift_imm_vec_exact_top")
> +	     ] UNSPEC_RSHRN)
> +	  (unspec:<VNARROWQ> [
> +	      (match_operand:VQN 3 "register_operand" "w")
> +	      (match_dup 2)
> +	     ] UNSPEC_RSHRN)))]
> +  "TARGET_SIMD"
> +  "uzp2\\t%0.<V2ntype>, %1.<V2ntype>, %3.<V2ntype>"
> +  [(set_attr "type" "neon_permute<q>")]
> +)
> +
>  (define_expand "aarch64_shrn<mode>"
>    [(set (match_operand:<VNARROWQ> 0 "register_operand")
>  	(truncate:<VNARROWQ>
> diff --git a/gcc/config/aarch64/predicates.md
> b/gcc/config/aarch64/predicates.md
> index
> 49f02ae0381359174fed80c2a2264295c75bc189..7fd4f9e7d06d3082d6f30472
> 90f0446789e1d0d2 100644
> --- a/gcc/config/aarch64/predicates.md
> +++ b/gcc/config/aarch64/predicates.md
> @@ -545,6 +545,12 @@ (define_predicate
> "aarch64_simd_shift_imm_offset_di"
>    (and (match_code "const_int")
>         (match_test "IN_RANGE (INTVAL (op), 1, 64)")))
> 
> +(define_predicate "aarch64_simd_shift_imm_vec_exact_top"
> +  (and (match_code "const_vector")
> +       (match_test "aarch64_const_vec_all_same_in_range_p (op,
> +			GET_MODE_UNIT_BITSIZE (GET_MODE (op)) / 2,
> +			GET_MODE_UNIT_BITSIZE (GET_MODE (op)) / 2)")))
> +
>  (define_predicate "aarch64_simd_shift_imm_vec_qi"
>    (and (match_code "const_vector")
>         (match_test "aarch64_const_vec_all_same_in_range_p (op, 1, 8)")))
> diff --git a/gcc/testsuite/gcc.target/aarch64/shrn-combine-2.c
> b/gcc/testsuite/gcc.target/aarch64/shrn-combine-2.c
> new file mode 100644
> index
> 0000000000000000000000000000000000000000..924b3b849e449082b8c0b7
> dc6b955a2bad8d0911
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/shrn-combine-2.c
> @@ -0,0 +1,15 @@
> +/* { dg-do assemble } */
> +/* { dg-options "-O3 --save-temps --param=vect-epilogues-nomask=0" } */
> +
> +typedef short int16_t;
> +typedef unsigned short uint16_t;
> +
> +void foo (uint16_t * restrict a, int16_t * restrict d, int n)
> +{
> +    for( int i = 0; i < n; i++ )
> +      d[i] = (a[i] * a[i]) >> 16;
> +}
> +
> +/* { dg-final { scan-assembler-times {\tuzp2\t} 1 } } */
> +/* { dg-final { scan-assembler-not {\tshrn\t} } } */
> +/* { dg-final { scan-assembler-not {\tshrn2\t} } } */
> diff --git a/gcc/testsuite/gcc.target/aarch64/shrn-combine-3.c
> b/gcc/testsuite/gcc.target/aarch64/shrn-combine-3.c
> new file mode 100644
> index
> 0000000000000000000000000000000000000000..929a55c5c338844e6a5c5ad
> 249af482286ab9c61
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/shrn-combine-3.c
> @@ -0,0 +1,14 @@
> +/* { dg-do assemble } */
> +/* { dg-options "-O3 --save-temps --param=vect-epilogues-nomask=0" } */
> +
> +
> +#include <arm_neon.h>
> +
> +uint16x8_t foo (uint32x4_t a, uint32x4_t b)
> +{
> +  return vrshrn_high_n_u32 (vrshrn_n_u32 (a, 16), b, 16);
> +}
> +
> +/* { dg-final { scan-assembler-times {\tuzp2\t} 1 } } */
> +/* { dg-final { scan-assembler-not {\tshrn\t} } } */
> +/* { dg-final { scan-assembler-not {\tshrn2\t} } } */
> 
> 
> --

  reply	other threads:[~2021-09-30  8:54 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-29 16:19 [PATCH 0/7]AArch64 Optimize truncation, shifts and bitmask comparisons Tamar Christina
2021-09-29 16:19 ` [PATCH 1/7]AArch64 Add combine patterns for right shift and narrow Tamar Christina
2021-09-30  8:50   ` Kyrylo Tkachov
2021-10-06 14:32     ` Richard Sandiford
2021-10-12 16:18       ` Tamar Christina
2021-10-12 16:35         ` Kyrylo Tkachov
2021-09-29 16:19 ` [PATCH 2/7]AArch64 Add combine patterns for narrowing shift of half top bits (shuffle) Tamar Christina
2021-09-30  8:54   ` Kyrylo Tkachov [this message]
2021-10-12 16:23     ` Tamar Christina
2021-10-12 16:36       ` Kyrylo Tkachov
2021-09-29 16:20 ` [PATCH 3/7]AArch64 Add pattern for sshr to cmlt Tamar Christina
2021-09-30  9:27   ` Kyrylo Tkachov
2021-10-11 19:56     ` Andrew Pinski
2021-10-12 12:19       ` Kyrylo Tkachov
2021-10-12 16:20         ` Tamar Christina
2021-09-29 16:20 ` [PATCH 4/7]AArch64 Add pattern xtn+xtn2 to uzp2 Tamar Christina
2021-09-30  9:28   ` Kyrylo Tkachov
2021-10-12 16:25     ` Tamar Christina
2021-10-12 16:39       ` Kyrylo Tkachov
2021-10-13 11:05         ` Tamar Christina
2021-10-13 12:52           ` Kyrylo Tkachov
2021-09-29 16:21 ` [PATCH 5/7]middle-end Convert bitclear <imm> + cmp<cc> #0 into cm<cc2> <imm2> Tamar Christina
2021-09-30  6:17   ` Richard Biener
2021-09-30  9:56     ` Tamar Christina
2021-09-30 10:26       ` Richard Biener
2021-10-05 12:55         ` Tamar Christina
2021-10-13 12:17           ` Richard Biener
2021-09-29 16:21 ` [PATCH 6/7]AArch64 Add neg + cmle into cmgt Tamar Christina
2021-09-30  9:34   ` Kyrylo Tkachov
2021-09-29 16:21 ` [PATCH 7/7]AArch64 Combine cmeq 0 + not into cmtst Tamar Christina
2021-09-30  9:35   ` Kyrylo Tkachov

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